Electronic article surveillance (EAS) is a system used to detect when articles leave a designated area. These systems typically include a tag or marker that is attached to an article, such as a retail item for sale, a broadcasting antenna that broadcasts an interrogation signal and a receiving antenna that receives a response signal generated by the tag or marker in response to the interrogation signal.
In some EAS systems, the interrogation signal is generated at exits from the area and when a response signal is detected from a tag or marker, an alert is issued indicating that the article is moving toward an exit. In other embodiments, the tag on the article is periodically interrogated by the interrogation signal to ensure that the article remains within the area. When the article leaves the area, as indicated by the response signal not being received, an alert is generated.
Such EAS systems are used extensively in retail environments where retail items for sale have a tag or marker attached to them. Such tags or markers are typically disabled at a point-of-sale by either removing the tag from the item or applying a disabling signal that alters the tag or marker so that it no longer generates a response signal when it passes through the interrogation signal. This prevents purchased retail items from triggering an alarm as they are taken out of the store.
The discussion above is merely provided for general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter. The claimed subject matter is not limited to implementations that solve any or all disadvantages noted in the background.